Sheet metal chimneys



Aug. 11, 1959 H. s. McKANN SHEET METAL CHIMNEYS Filed Feb. 24, 1956 3 Sheets-Sheet l ATTORNEYIS Aug. '11, 1959 H. s. MCKANN 2,898,839

8 I SHEET METAL CHIMNEYS I Filed Feb. 24, 1956 5 Sheets-Sheet 2 ATTORNEYS Aug. 11, 1959 H. s. MCKANN SHEET METAL CHIMNEYS 5 Sheets-Sheet 3 Filed Feb. 24, 1956 ATTORNEYS This invention relates to sheet metal chimneys and building constructions employing the same, and particularly to prefabricated or package chimneys.

In its preferred embodiments, the invention pertains toprefabricated chimneys of the type in which the flue or smoke pipe is air cooled. One chimney construction of this general type is disclosed in my Patent 2,713,301, issued July 19, 1955.

In the construction of modern housing facilities, and particularly in houses of the moderate or intermediate price range, there is a growing tendency to employ prefabricated sheet metal chimneys rather than chimneys of brick construction. Such chimneys are at least partially assembled by the manufacturer and then shipped to the point of use, one great advantage being that installation by the builder requires relatively little labor. As pointed out in detail in Patent 2,713,301, it is now the practice to so construct such chimneys that cool air is inducted into the chimney structure and caused to pass upwardly about the flue or smoke pipe, so reducing the heat transfer from the flue or smoke pipe to the adjacent building structure. Advantageously, such chimneys may also use the flow of the cooling air to increase the draft of the chimney in accordance with the air-jet principle disclosed in Patent 2,713,301.

While the prefabricated metal chimneys now in use have achieved considerable success, they have also presented disadvantages which are eliminated by the present invention. One disadvantage has been the fact that priorart sheet metal chimney constructions have not been well suited for buildings employing a so-called cathedral roof. Another drawback has been the relative bulkiness of the assembly in the form shipped by the manufacturer, and the resulting high freight rate. In fact, the size of the chimney pakage" as shipped by the manufacturer has been entirely out of proportion with the weight of the chimney, so that the actual cost of the product to the purchaser was frequently substantially increased, in proportion to the distance between the manufacturer and the point of installation. Finally, while the installation of such prefabricated chimneys is very simple and inexpensive in comparison with brick chimneys, the installation still required a material amount of labor and expense which can desirably be reduced.

In general, the present invention is directed toward eliminating or minimizing such disadvantages.

A particular object of the invention is to provide a simplified, economical chimney structure of the type referred to which is particularly useful in building structures having a cathedral roof or a roof of relatively.

which can be installed with considerably less laborthan- In this connection,

has heretofore been possible.

States Patent 2,898,839 Patented Aug. 11, 1959 chimneys constructed in accordance with the present invention can be installed in a few minutes, as compared to an hour or more for prior-art chimneys.

Yet another object is to provide a simplified building construction in which the sheet metal chimney components are supported from the chimney casing above the roof and require no mounting or support below the roof level.

In order that these and other advantages of the invention may be understood in detail, reference is had to the accompanying drawings, which form a part of this specification, and wherein:

Fig. 1 is a vertical sectional view of a building construction in accordance with one advantageous embodiment of the invention;

Fig. 1 is a detail vertical sectional view, illustrating a portion of Fig. l on increased scale for clarity;

Fig. 2 is a horizontal sectional view taken on line 22,

Fig. 1;

Fig. 3 is a horizontal sectional view taken on line 3 -3, Fig. 1; r

Fig. 7 is a vertical sectional view, similar to Fig. 1,

of another embodiment of the invention, and

I Fig. 8 is a vertical sectional view, similar to Fig. l,

of a further embodiment of the invention.

Referring now to the drawings in detail, and first to Figs. l-S thereof, it will be seen that the embodiment of v the invention here illustrated includes a low-pitch roof 1 provided with an opening 2 surrounded by an upstanding casing 3. The casing has vertical sheet metal sidewalls 4 joined to form an open-top enclosure of square cross-section, and is completed by a cap 5 supported by vertical struts 6. Cap 5 is in the form of an inverted pan with its dependent sides spaced from the walls 4 of the casing to provide an exit for the gases rising through the chimney casing.

The casing 3 is mounted on roof 1 by means of a flashing unit illustrated in detail in Figs. 3 and 4, this flashing unit per se forming the subject matter of my copending application, Serial Number 567,584, now Patent No. 2,800,850, filed concurrently herewith.

The flashing unit is constructed in two halves 7 and 8, Fig. 4, adapted to be moved into overlapping relationship to embrace the intermediate air pipe 9 of the chimney duct unit hereinafter described. Each half of the flashing unit includes a flat sheet metal base 10, 10' of generally rectangular form and provided with a notch 11, 11', respectively. Each notch has a semi-circular bottom of such size as to fit the periphery of air pipe 9,

and straight sides to allow free entry of the air pipe.-

webs spot welded to the base elements. The flange members 12, 12 are of such size and shape that the upstanding webs 13, 13' thereof will be received within the bottom end of the casing 3 when the flashing unit is assembled.

As seen in Fig. 4, the base member 10 of the flashing unit is provided with slots 14 closely adjacent and parallel to the portions of flange member 12 which lie parallel to the sides of notch 11. Thus, when the two halves of the flashing unit are brought together by sliding base r 3 v member-10 und'er member 10, the ends 15 of the flange member 12' enter into the slots 14. In this connection, it will be understood that the ends 15 of flange member 12, are spaced somewhat more closely together than are the ends of flange member 12" so that, when notches 11, 11" are aligned, ends 15 are aligned with slots 14.

When the flashing unit is assembled-about the air pipe 9, it is nailed in place on the roof 1; as seen in Fig. 1. The casing is then placed in position and mounted by means of brackets 3 Fig. 3, using sheet metal screws or other suitable fasteners. As seen in Fig. 5 the overlapped portions of the flashing members do not originally lie flush in face-to-face contact because the base web of flange member 12 intervenes. However, both the base sheets 10, and the flange members 12, 12' may be of relatively light, sheet metaL Qn the orderof 30 gauge, for example, so that nailing. of the flashing in place brings the base sheets together at their edges, as seen in Fig. 5

Referring again to Fig. 1, .it will be seen that the chimney assembly comprises, in addition to the intermediate air pipe 9, an inner smoke pipe or flue 16 and an outer air pipe 17, all preferably concentrically arranged. Intermediate air pipe 9 is in three telescoped sections 9%, 9 and 9. Flue or smoke pipe 16 is also telescopic, comprising two sections 16 and 16 Outer air pipe 17 also is. telescopic, including two sections 17 and.l7 At its bottom end, outer air. pipe 17 is closed by a plate 18 having an outer annular flange 18 fastened to the outer pipe, as by sheet metal screws, and a centrally disposed circular opening engaging the periphery of the smoke pipe 16 below bead 19.

The top of upper section 16 of the flue or smoke pipe is rigidly connected to-section 9 of the intermediate air pipe by a metal strap 20. The lower end of bottom section 9 of intermediate air pipe is rigidly connected with bottom closure plate 18 by circumferentially spaced links 21 welded at one end to the intermediate air pipe and at the other end, provided with bent out portions secured to plate 18 by-sheet metal screwsor the like. sections 9 of the intermediate air pipe and 17 of the outer air pipe is disposed a hexagonal spacing member 22,

Fig. 2, secured to section 9 of the intermediate air pipe,

as by sheet metal screws at points 23. Metalstraps24 are secured at one end to member 22 and extend downwardly and outwardly, their lower ends being secured to the inner surface of section 17 of the outer air pipe.

The telescopic joints between sections 16 and 16 of the smoke pipe, and sections 17 and 17 of-the outer air pipe, are simple slip joints. The ends of the telescoped sections of intermediate air pipe 9, however, are provided with rolled beads, as illustrated in Fig. 1 the bead on the outermost member being internal and that'on the innermost member being external. Thus, with pipe 9 fully extended, section 9 thereof is supported fi'om section 9 while section 9 is in turn supported from section 9 hand, upper section 17 of the outer air pipe is supported from the middle section 9 of the intermediate air pipe, by straps 24, while top section 16 of the smoke pipe is similarly supported by strap 20. duct assembly are supported by the intermediate air pipe 9.

At its top end, upper section 9 of the intermediate air pipe is provided with a reenforcing collar 25,a.nd, at dia metrically spaced points, a pair of outwardly offset, downwardly projecting lugs 26, Figs. 3-5. As best seen in Fig. 4, base element 10 of the flashing unit. is provided with a pair ofbrackets 27. Brackets 27 are of-right angle Between,

Since bottom closure plate 18 is rigidly connected. both to the lowermost section 9 of intermediate pipe 9- Thus all parts of, the

" f a sess d the other web extending vertically upward therefrom. Brackets 27 are spaced apart by a distance such that the vertically extending webs thereof are slightly closer together than the downwardly projecting lugs 26. Thus, lugs 26 engage over the vertical webs of brackets 27 to provide means for supporting the intermediate air pipe 9, and thus the entire duct assembly.

In the preamble, reference is made to low pitch roofs commonly known as of the cathedral type. With such roofs, the space between the roof and ceiling is relatively small, and, moreover,.varies from point to point, over a wide area. Thetelescopic structure of the present invention is particularly well adapted for installation in this type of building.

To install this chimney structure in a building, the hole 2 is first cut in the roof, large enough to accommodate the outer pipe 17, and the chimney duct assembly, comprising pipes 9 16 and 1,7, is lowered through the hole into approximate position. The two halves of the flashing unit are then slid into place, with notches 11, 11' thereof engaging the periphery of top section 9' of the intermediate, air pipe. The duct assembly is then adjusted about its axis until lugs 26 are aligned with brackets 27, the duct assembly thenbeing lowered into final position with the assembly being supported by interengagement of; lugs 26 and brackets 27., In this connection, it will benotedthat the lower end of the duct assembly,

defined by closure member 18, should be positioned at the ceiling line. To make certain that, thisoccurs, the telescopic structure may beyadjusted to the desired length before being loweredinto place. Alternately, the duct assembly may be, provided with means for adjustment, advantageously with such means being operable from the roof after the duct assembly is lowered into place. Thus,

as seen in Fig. 1, such means may take the form of a.

the free ends thereof being then nailed to the roof through the flashing in such manner that the strapping. is tensioned across the top of intermediate pipe section 9.

The casing 3 is then placed inposition on the flashing unit andsecured thereto by means of brackets 3.

9 Considering now the completed assembly as shown in Fig. 1, it will be noted that the outer air pipe 17 is open.

at the top and therefore communicates with the air space immediately below roof 1. annular space, between outer pipe 17 and intermediate pipe 9 communicates-with the annular space between intermediate pipe 9 andflue or smoke pipe 16, and that this,

latter annular spaceopens into the interior of-casing 3. The interior of the casing is otherwise closed, at the bottom, by the flashing unit which constitutes a diaphragm. When the flue 16 is in operation, air in the annular space between such flue and the intermediate pipe 9 is heated, and therefore rises, thus inducing air from the space below the roof: to enter the space between pipes 17 and 9, which air flows downwardly through such space into the spacebetween pipes 9 and.16, and thence upwardly about pipe 16, into casing3, and out to they atmosphere through chimney cap 5.

It will be noted that,- in this embodiment, the smoke pipe 16 terminates short of the upper end. of the inter.-

mediatepip so that this construction provides an airjet action as described in my aforementioned Patent 2,713,301. It is tov be understood, however, that the improvements of. the present invention can be applied ad scribed is its; adaptability for shipment ina single pack-.- cross section, havmg one web secured vtoelement 10tand: age, rather;thanseveral separate packages. asheretofore;

It will also be seen that the.

required. As seen in Fig. 6, the complete duct system, comprising pipes 9, 16 and 17, telescopes or collapses to a size such that it may be disposed substantially entirely within the confines of casing 3, the length of each of the sections of all of said pipes being approximately the same as the height of said casing, including the cap 5. For packaging, the flashing unit is disposed beside the casing 3, and the entire structure then placed in a single shipping container.

A simplified embodiment of the invention is illustrated in Fig. 7. Here, only the intermediate air pipe 109 is telescopic, comprising an upper' section 109 and a lower section 109". The outer pipe 117 is a single piece, closed at the bottom by plate 118. Again, plate 118 has a central opening engaging the periphery of smoke pipe 116 beneath bead 119. The bottom end of section 109 of the intermediate air pipe is connected rigidly to plate 118 by legs 121. Thus, outer pipe 117 and smoke pipe 116 are both supported by section 109 of the intermediate pipe and, because of the beaded ends of sections 109 and 109*, the entire assembly depends from supporting lugs 126 engaging brackets (not shown) on the flashing 110-113, in the same manner described with reference to the embodiment of Figs. 1-6. It will thus be seen that the structure of Fig. 7 has all the characteristics of the longer chimney structure of Figs. 1- 6, except that it is unnecessary here to provide elements equivalent to straps 20 and- 24, Fig. 1.

In the embodiments of Figs. 1 and 7, the special flashing unit of Fig. 4 is employed, so that the flashing unit closes the space between the casing and the top of the intermediate air pipe. Further, these two constructions are characterized by the fact that, since the flashing unit acts as a diaphragm across the casing at the bottom thereof, air must be inducted into the outer air pipe from below the roof. It will be understood that the top of the intermediate air pipe can be connected with a diaphragm extending across the chimney casing or box at any desired point. Further, if the diaphragm is sufiiciently high in the casing, outside air may be inducted into the duct assembly via the portion of the casing below the diaphragm.

In this connection, reference is had to Fig. 8, illustrating a chimney constructed in the manner just mentioned. Here, casing 203 is supported on roof 201 by conventional flashing 210, the flashing extending into contact with the periphery of outer pipe 217 to close the bottom of the casing. Like the embodiments of the invention previously described, casing 203 is provided with a chimney cap 205 supported on struts 206 Struts 206 are provided with ears 206', substantially at the top of casing 203. A sheet metal diaphragm 230 extends across the casing top and is secured to ears 206', as by sheet metal screws, the diaphragm being provided withsuitably positioned apertures to accommodate the struts 206. At its center, diaphragm 230 is provided with acircular opening having an upstanding flange. The upper end of top section 209 of the intermediate air pipe 209 extendsthrough said opening and is rolled over hefl nsei q thawin depends solely o the diaphragm 230.

Intermediate air pipe 209 comprises telescoped sections 209 and 209 the latter being rigidly attached at its lower end to annular closure plate 218 by legs 221. The bottom of outer pipe 217 is rigidly connected to plate 218, so that the plate 218 closes pipe 217 but the space between that pipe and pipe 209 communicates with the interior of pipe 209. Smoke pipe 216 extends through the central opening of annular plate 218 and is provided with an exterior bead resting on the top of plate 218. Thus, single section pipes 217 and 216 are both supported by dual section, telescopic, intermediate pipe 209.

At its lower end, section 209 is provided with an outwardly rolled bead. At its upper end, section 209 is 6 provided with an inwardly rolled bead. These beads respectively engage the inner surface of section 209 and the outer surface of section 209 to provide a sliding joint of such stiflness that, while the effective length of pipe 209 can be adjusted manually, pipe 209 will support the remainder of the duct assembly without further sliding of the joint. Thus, pipes 217 and 216 are supported from diaphragm 230 solely through telescopic pipe 209.

It will be noted that outer pipe 217 extends well above the roof level into the interior of casing 203, and that the casing is provided with side openings at 231. Thus, outside air is inducted through the casing below diaphragm 230 into the space between outer pipe 217 and intermediate pipe 209. Air flow in the duct system is otherwise as explained hereinbefore with reference to Figs. 1-7.

While the embodiments discussed have been chosen to illustrate certain advantageous features, it is obvious that various modifications can be made without departing from the scope of the invention. Thus, for example, the outer pipe 17, Fig. 1, may extend upwardly into the casing 3, to provide additional insulation between the smoke pipe and the roof, air then being inducted into the air duct system through the casing instead of from below the roof level. Similarly, in Fig. 1, the entire duct assembly may depend from a diaphragm extending across the interior of the casing at any desired point, rather as the diaphragm.

\ I claim:

' 1. In a building construction, the combination of a roof having an opening; a hollow chimney casing mounted on said roof surrounding said opening and extending upwardly therefrom, said casing having an exhaust opening communicating with the atmosphere; an intermediate air pipe comprising a plurality of telescopically engaged sections and being adjustable in length by relative axial movement of such sections, said intermediate air pipe being disposed in alignment with said opening in said roof and extending therethrough; first closure means extending between the walls of said casing and the uppermost section of said intermediate air pipe and closing the space therebetween against air flow; means fixed to said intermediate air pipe and engaged over said first closure means to suspend said intermediate air pipe from said first closure means; an outer air pipe surrounding said intermediate air pipe; a smoke pipe disposed within said intermediate air pipe; second closure means mounted on said intermediate air pipe at the bottom thereof and extending between said outer air pipe and said smoke pipe to close the space therebetween against air flow, there being an opening communicating between the space between said outer and intermediate air pipes and the space between said intermediate air pipe and smoke pipe above said second closure means, whereby air may flow downwardly between said outer and intermediate air pipes to a point adjacent said second closure means and hence upwardly between said intermediate air pipe and smoke pipe into said casing, and said smoke pipe and outer air pipe each being provided with means engaging said second closure means for vertical support of said smoke pipe and outer air pipe.

2. The construction defined in claim 1 and in which said outer air pipe and smoke pipe each include two telescopically engaged sections, the upper section of said outer air pipe and the upper section of said smoke pipe each being provided with means connecting the same to the upper section of said intermediate air pipe for vertical support thereby.

3. The construction defined in claim 1 and wherein said outer air pipe comprises a single unit of pipe connected to and supported by said second closure means.

4. In a building construction, the combination of a roof having an opening; a hollow casing mounted on said 7 roof, saidcasing being'larger than said opening, surrounding the same and extending upwardlytherefrom, said' casing having an exhaust opening communicating with the atmosphere; a collapsible duct assembly capable of beinglowered bodily through said opening in the. root, said assembly being aligned vertically with respect to saidcasing and comprising a smoke pipe, an intermediate air pipe surrounding said smoke pipe and. an outer air pipe. surrounding said intermediate air pipe, at least saidintermediate air pipe being formed of telescopic sections,,said intermediate air pipe, extending upwardly through said opening in the roof into said casing and being spaced inwardly from the walls of said casing, the, upper end of said outer air pipe being disposed at a point belowthe upper end of said intermediate air pipe and. said outer. air pipe extending downwardly at least to the lower. end. of said intermediate air pipe; a transversely disposed plate closing the space between the lower end of said outer. air

pipe and said smoke pipe, said plate being attached to.

said outer air pipe and having an opening through. which.

said smoke pipe extends, said smoke pipe having means. engaging the upper surface of said plate whereby" said smoke pipe is supported by said plate; supporting meanspositively connecting said plate to said. intermediate air. pipe, whereby both said outer air pipe and said smoke. pipe are supported by and depend from said intermediate air pipe by reason of their connection. to saidplate; 'clo. sure means in the nature of a fixed diaphragm separate from said roof bridging the space between: said. casing:

and said intermediate air pipe, means rigidly mounting saidclosure means at apoint bove said'; opening in the roof and below said exhaust opening, and; laterally extending means fixed to said intermediate air. pipe and; engaged with said closure means. to support said duct assembly from said closure means, said. duct. assembly including an opening adjacent and above said plate and. communicating between the space. betweensaid outer: and. intermediate air pipes and the space between said inter mediate air pipe and saidsmoke pipe, whereby air can flow downwardly between said outer and. intermediate.

air pipes and then upwardly between said intermediate air pipe and smoke pipe and into said casing;

5. A building construction in accordance with;claim.4

gagement with said intermediate air-pipe, said outer air' pipe extending through said opening in said roof into the interior of said casing, the upper end of said outer air pipe being disposed below said diaphragm. I

7. A building construction in accordance with claim 4 and wherein the telescopic sections of said intermediate air pipe engage each other in a relatively tight friction fit capable of manual adjustment lengthwise of the duct assembly but sufliciently'tight to remain inany desired adjusted position and afiord complete support for said outer air pipe and smoke pipe. i

8. In a prefabricated chimney, the combination of a hollow casing constructed to be mounted on a building roof and having one end open; a diaphragm extending across said casing and having an opening therein;. a duct assembly comprising a smoke pipe, an intermediate air pipe surrounding said smoke pipe and an outer air pipe surrounding said intermediate air. pipe, all of said pipes being made up of a plurality of telescoping sections whereby the pipes can be collapsed endwise into a relatively short space for shipping or extended to form a relatively long duct assembly in use, the length of the longest of said sections being substantially no greater than that of the casing, and said casing beingglarger in transverse dimension than said outer air pipe, whereby the entire duct assembly, when. collapsed, can be housed within said casing, said duct assembly comprising a bot tom closure member mounted on said intermediate air pipe and fixed to said outer air. pipe, said closure member having an opening throughwhich said smoke pipe extends and said smoke pipe including. a lateral projection.

engaged over said closure member; means fixedly'mount-- ing said diaphragm on said casing; and means fixed to the upper end of said intermediate air pipe and engageable over said diaphragm, when the upper end. of said.

intermediate air pipe-is dispose/din said openin in said diaphragm, to support the entire duct assembly.

9. A building construction in accordancc'with' claim 4 and wherein said outer airpipe and smoke pipe-areeach made up of two telescoping sections,- the telescopic,

sections of said intermediate air pipe being provided with interengaging beads. effective as stop means to limit ex.- tension of said intermediate air pipe to a predetermined length, the upper sections of said outer air pipe and.

smoke pipeeach being rigidly'connected-to a section of said intermediate air pipe.

10. A building construction in accordance with claim 1 and further comprising adjusting. means operable manually from said roof for adjusting the axialpositions of said telescopic sections, said adjusting means including an elongated member having one end disposed at said roof and the other end attached toone of said telescopic sections, said elongated member extending within said intermediate air pipe.

ReferencesCited in the file of this patent UNITED STATES. PATENTS Thulman Apr. 14, 1953 

